From Surface to Sump: A Glossary of Cave Terms Every New Caver Should Know

Every subculture develops its own vocabulary, and caving is no exception. Listen to a group of experienced cavers plan a trip and you will hear words like sump, squeeze, pitch, and survey thrown around as casually as weather talk. For newcomers, this language can feel like a wall. The fastest way over that wall is to learn the terms before your first serious trip, so you can follow along, ask useful questions, and understand what you are actually signing up for.

Start with the basics of cave structure. A passage is any route through the cave, from a walking-size corridor to a crawl. A chamber is a large open space, and a sump is a section of passage completely filled with water, which usually requires diving gear to pass. A pitch is a vertical drop that requires rope or a ladder, and a squeeze is a passage tight enough that you must remove gear or turn sideways to get through.

Terms for Movement and Navigation

Once you understand the landscape, learn the verbs. To rig a pitch means to set up the rope and anchors for a descent. To derig means to take it all down. To free climb is to climb without a rope, which cavers do only on easy, low-exposure rock. A handline is a rope used for balance on steep but non-vertical ground, not for fall protection.

Navigation has its own shorthand. A survey is a measured map of the cave, and surveying is the slow, careful process of creating one with compass, clinometer, and distance measurements. A station is a marked point in the survey. A lead is an unexplored passage that might go somewhere. Cavers get genuinely excited about leads, because a lead is a question the cave has not yet answered.

Then there is the gear vocabulary. A harness is the webbing system you wear for rope work. A cowstail is a short tether that connects your harness to an anchor. A descender is the device that controls your speed on a rope. A rack and a bobbin are two common descender types, and cavers have strong opinions about both. A maillon is a small metal link used to connect things, and a krab is a carabiner, because cavers shorten everything they can.

Words That Describe the Cave Itself

Cave features have names too. A stalactite hangs from the ceiling, a stalagmite rises from the floor, and a column is what you get when the two meet. Flowstone is the smooth, draped calcite that coats walls and floors. A gour is a rimstone dam that holds a small pool. Moonmilk is a soft, white deposit with a texture somewhere between cream cheese and wet chalk. Scallops are the curved hollows carved into rock by flowing water, and they tell you which direction the water once moved.

Finally, learn the human terms. A caver is someone who explores caves, while a spelunker is sometimes used for a casual visitor, though the distinction is blurry and regional. A trip leader is the person responsible for planning and safety. A callout is the time by which you have promised someone on the surface to be out, and it is one of the most important words in the entire glossary. Respect your callout, always.

You do not need to memorize all of this before your first trip. But learning a handful of terms each time you go will make you a better partner, a safer caver, and a more welcome presence in any group.